Solid ink or phase change ink imaging devices, hereafter called solid ink printers, encompass various imaging devices, such as printers and multi-function devices. These printers offer many advantages over other types of image generating devices, such as laser and aqueous inkjet imaging devices. Solid ink or phase change ink printers conventionally receive ink in a solid form, either as pellets or as ink sticks. A color printer typically uses four colors of ink (yellow, cyan, magenta, and black).
The solid ink pellets or ink sticks, hereafter referred to as ink, sticks, or ink sticks, are delivered to a melting device, which is typically coupled to an ink loader, for conversion of the solid ink to a liquid. A typical ink loader includes multiple feed channels, one for each color of ink used in the imaging device. Each channel has an insertion opening in which ink sticks of a particular color are placed and then either gravity fed or urged by a conveyor or a spring-loaded pusher along the feed channel. Each feed channel directs the solid ink within the channel towards a melting device located at the end of the channel. Each melting device receives solid ink from the feed channel to which the melting device is connected and heats the solid ink impinging on it to convert the solid ink into liquid ink that is delivered to a print head for jetting onto a recording medium or intermediate transfer surface.
Each feed channel insertion opening may be covered by a key plate having a keyed opening. The keyed openings help ensure a printer user places ink sticks of the correct color in a feed channel. To accomplish this goal, each keyed opening has a unique shape. The ink sticks of the color corresponding to a particular feed channel have a shape corresponding to the shape of the keyed opening. The keyed openings and corresponding ink stick shapes exclude from each ink feed channel ink sticks of all colors except the ink sticks of the proper color for the feed channel. Unique keying shapes for other factors are also employed in keyed openings to exclude from a feed channel ink sticks that are formulated or intended for other printer models.
As the number of pages printed per minute increases for solid ink printers so does the demand for ink in the printer. To supply larger amounts of ink to printers, the cross-sectional area of the feed channels may be increased. Consequently, the insertion openings for the channels and the keyed plates covering the openings are likewise enlarged. These larger openings enable smaller solid ink sticks to pass through without engaging the keyed plates over the openings. Thus, solid ink sticks that do not conform to the appropriate color for a feed channel can be loaded into the feed channel and delivered to the melting device at the end of the feed channel. Even if the ink stick is the correct color, the stick may be include an ink formulation that has different chemical properties than those best suited for proper operation of the printer. In some situations, an ink stick may be the correct color for a feed channel and possess the chemical properties required for operation in the feed channel, but the size of the ink stick may impair the ability of the stick to cooperate with guiding structure within the feed channel.
To help ensure that each feed channel in a solid ink printer is loaded only with ink sticks configured for transport within the feed channel, systems have been developed that identify a solid ink stick before it is inserted in a feed channel. One such system provides a sensor at each ink stick insertion area for each feed channel in a solid ink printer. A mechanized barrier separates the insertion area from the feed channel. The barrier moves to enable an ink stick to enter the feed channel only in response to the ink stick being identified as one configured for transport through the feed channel. In another system that identifies ink sticks, an insertion port that is common to all of the feed channels is separated from the feed channels in a solid ink printer. A transport system moves an ink stick from the insertion port to its corresponding feed channel only in response to the ink stick being identified as one configured for the feed channel.
While these systems are effective for loading feed channels only with the ink sticks configured for a feed channel, they do not intelligently process ink sticks that do not correspond to a feed channel. For example, the system that uses a mechanized barrier to block the entrance to a feed channel simply remains in the blocking position in response to an ink stick failing the identification process. In order to enable the insertion port to process other ink sticks, the operator must physically remove the ink stick from the insertion port. Similarly, the system that uses the transport system to deliver an identified ink stick to its corresponding feed channel may leave an ink stick failing the identification process in the single insertion port. If the ink stick is left in the single insertion port, the operator must physically remove the ink stick from the single insertion port so another ink stick may be subjected to the identification process. Informing the operator of the reason for the rejection of the ink stick and providing the operator with options for dealing with the ink stick would be beneficial.